Draw-ironed aluminum cans that have heretofore been widely used for beverage cans are the ones that are obtained by draw-ironing a resin-coated aluminum sheet under dry conditions using neither aqueous lubricant nor coolant, the resin-coated aluminum sheet being the one obtained by coating a metal blank with an organic film.
As the resin-coated metal sheet used for the draw-ironed aluminum cans, there has been used the one on which is laminated a film of polyethylene terephthalate or polyethylene terephthalate/isophthalate. For example, there has been proposed the one having a double-layer resin coating comprising a polyethylene terephthalate/isophthalate containing 3 to 13 mol % of isophthalic acid as an upper layer, and a polyethylene terephthalate/isophthalate containing 8 to 25 mol % of isophthalic acid as a lower layer (patent document 1).
To decrease the cost of production of can bodies in recent years, attempts have been made to decrease the thickness of the can bodies in order to decrease the amount of blank used for the can bodies. When the draw-ironed aluminum can having such a decreased thickness is used as a beverage can that is filled with a content, however, it is probable that the aluminum sheet forming the side wall is ruptured and the content gushes out when the body wall of the can is dented in the step of delivery since the thickness of the body wall has been extremely decreased.
In order to solve the above problem, the present inventors have proposed a seamless aluminum can having improved stab strength (patent document 2).